Retreps

Retreps, a term often found in the context of vintage technology and computer history, refers to a specific type of memory technology used in early computer systems. It is derived from the concept of "read-only" memory, but with a twist. Unlike traditional ROM which was permanently programmed during manufacturing, retreps offered a limited form of re-programmability. The 're' in retreps signifies this ability to be written to or modified, albeit with considerable effort and specialized equipment. This made it distinct from PROM (Programmable Read-Only Memory) which could only be programmed once.

The primary advantage of retreps was its flexibility compared to standard ROM, allowing for updates or corrections to firmware without requiring a complete chip replacement. However, this re-programmability was not as straightforward or fast as modern erasable programmable read-only memory (EPROM) or flash memory. The process often involved high voltages or specific erasure methods, making it a task for trained technicians rather than end-users. Consequently, retreps occupied a niche, providing a middle ground between permanent storage and fully dynamic RAM. Its use was primarily in embedded systems and early personal computers where firmware modifications were anticipated but not a frequent occurrence.